But to make his certainty more sure, and at the same time to show that he had no suspicion anyone was hiding in the room, he carried the letter over to the window, and at once he was aware of the spy's hiding-place.

It was not the bed hangings, but close at his side the heavy window curtain bulged.

The spy was at his very elbow; he had but to lift his arm--and of a sudden the letter slipped from his hand to the floor.

He did not drop it on purpose, he was fairly surprised; for looking down to read the letter he had seen protruding from the curtain a jewelled shoe buckle, and the foot which the buckle adorned seemed too small and slender for a man's.
Wogan had an opportunity to make certain.

He knelt down and picked up the letter; the foot was a woman's.